The present invention relates to implantable devices, and more particularly to a template system for use in conjunction with a multi-reservoir implantable pump.
Implantable pumps have been well known and widely utilized for many years. Typically, pumps of this type are implanted into patients who require the delivery of active substances or medication fluids to specific areas of their body. For example, patients that are experiencing severe pain may require painkillers daily or multiple times per day. Absent the use of an implantable pump or the like, a patient of this type would be subjected to one or more painful injections of such medication fluids. In the case of pain associated with more remote areas of the body, such as the spine, these injections may be painful for the patient. Furthermore, attempting to treat conditions such as this through oral or intravascular administration of medication often requires higher doses of medication and may cause severe side effects. Therefore, it is widely recognized that utilizing an implantable pump may be beneficial to both a patient and the treating physician.
Many implantable pump designs have been proposed. For example, U.S. Pat. No. 4,969,873 (“the '873 patent”), the disclosure of which is hereby incorporated by reference herein, teaches one such design. The '873 is an example of a constant flow pump, which typically include a housing having two chambers, a first chamber for holding the specific medication fluid to be administered and a second chamber for holding a propellant. A flexible membrane may separate the two chambers such that expansion of the propellant in the second chamber pushes the medication fluid out of the first chamber. This type of pump also typically includes an outlet opening connected to a catheter for directing the medication fluid to the desired area of the body, a replenishment opening for allowing for refilling of medication fluid into the first chamber and a bolus opening for allowing the direct introduction of a substance through the catheter without introduction into the first chamber. Both the replenishment opening and the bolus opening are typically covered by a septum that allows a needle or similar device to be passed through it, but properly seals the openings upon removal of the needle. As pumps of this type provide a constant flow of medication fluid to the specific area of the body, they must be refilled periodically with a proper concentration of medication fluid suited for extended release.
Thus, although these implantable devices dramatically decrease the amount of injections a patient is required to receive in order to treat a specific problem, a small number of injections are still required to regularly refill the implantable pump. These refilling injections are often difficult for a physician or other medical professional to administer, even though implantable pumps typically sit at or near the surface of a patient's skin, because of the lack of direct visibility of the pump and its openings. Furthermore, with each implantable pump generally including at least two different openings for admission of a needle therein, safety becomes a concern during refilling procedures. More particularly, it is vital that a long term supply of medication not be inadvertently directly injected into the patient through the aforementioned bolus port. Given the fact that the landscape of implantable pumps is changing to include more complicated multiple reservoir pumps, these safety concerns are often further exacerbated.
Therefore, there exists a need for a template system which decreases the difficulties and improves the safety of refilling procedures, especially during the refilling of multiple reservoir pumps or the like.